One well known receptacle used to connect and establish fluid communication between different medical components is known as a luer lock. Luer receptacles are widely used to connect syringes to medical instruments, such as needles, and to connect medical conduits to one another. In addition, luer lock receptacles have a standard configuration that allows different sizes and types of instruments to be connected to the same receptacle.
A conventional luer connection assembly typically includes a male luer tip component or fitting having a frustoconical shape which is inserted into a female luer component or fitting having a frustoconical shaped receiving cavity. Opposing conical surfaces come into contact with each other to form a sealed friction fit.
There are two general types of luer connection assemblies. One type is generally referred to as the luer slip, where the connection is maintained by the friction fit between the male luer tip and female luer component. The other type is generally referred to as a luer lock connection, whereby the male luer tip is encircled by an annular locking skirt having a threaded internal surface. The female component includes a corresponding single thread formed about the outer surface. Engaging the threaded skirt to the threaded outside surface establishes the connection between the male luer tip and female component while preventing accidental disconnects.
This conventional luer lock receptacle is used effectively throughout the world, but still has several disadvantages. One disadvantage is that the receptacle is prone to crack and break, particularly at the intersection of the skirt with the syringe barrel and at the intersection of the tapered post with the syringe barrel. This cracking and breaking compromises the strength of the mechanical connection between the receptacle and the adapter, and compromises the fluid tight seals between the receptacle and the adapter. Fluids leaking from the syringe are a particular problem as they can adversely affect a medical procedure, and also present a biological hazard to patients and medical personnel.
This situation may be compounded by medical devices or other instruments connected to a syringe receptacle, which may be relatively long or require aggressive manipulation by medical personnel. For example, harvesting of tissue and cells from different organs of the body, may require a relatively long cannula and aggressive manipulation by physicians, which may damage the receptacle. As there is only one point of contact between the thread on the female adapter and the threaded internal surface of the skirt, aggressive manipulation may cause the thread on the female component to crack or to completely shear off of the component, compromising the integrity of the luer connection.
In addition, the twisting motion required to lock the adapter to the receptacle, can cause the skirt to expand outwardly during engagement of the male threads on the adapter with the female threads on the receptacle. This expansion can also cause cracking and breaking to occur, or can cause micro cracks that lead to cracking and breaking.
In some instances, one receptacle may be used during more than one medical procedure. As each procedure requires the old adapter to be removed from the receptacle and a new adapter to be affixed thereto, there are multiple opportunities for an adapter to be over-torqued. Over-torqueing may result when the individual connecting the adapter to the syringe receptacle continues to twist the adapter after the opposing conical surfaces come into contact with each other to form a sealed friction fit. This over-torqueing may cause the tip of the tapered post to deform at the location where the tip interfaces with the adapter. Such deformation may cause the tip of the tapered post to become occluded, thereby reducing the amount of fluid that may flow through luer connection, thereby rendering the syringe receptacle effectively useless. In extreme instances, over-torqueing may cause the tapered post to fracture at the interface with the syringe receptacle. Over-torqueing may also result in damage at the intersection of the skirt with the syringe barrel and at the intersection of the tapered post with the syringe barrel.
Additionally, luer connections may be used to connect medical devices which are exposed to high pressure, such as injection of contrast media during angiographic procedures. During such procedures, the connection may exposed to pressures that may reach approximately 1200 pounds per square inch. As the rate of fluid injection is monitored and controlled during such angiographic procedures, any occlusion which decreases the amount of fluid being injected will adversely impact the administration of the procedure and result in inaccurate or wholly unusable test results.
Thus, there is a need in the art for an adapter for use in a luer lock connection which may permit users to securely tighten the adapter to the receptacle while preventing the user from over-torqueing the adapter. There is also a need in the art for an adapter which may reduce damage to the adapter and the receptacle from forces exerted perpendicular to the longitudinal axis of the adapter.